It is well known to apply detectors of electromagnetic radiation in, for instance, ellipsometry. And it is known to use beam splitters to direct portions of beams into different detectors which can be optimized to respond to different wavelength ranges. A Patent to Herzinger et al. U.S. Pat. No. 8,169,611, for instance shows such an arrangement in FIG. 1a thereof, reproduced as FIG. 6 herein for easy reference). Many other references showing similar application of beam splitters in a similar manner exist. Also known are monochromater systems that utilizes a sequence of gratings with which a beam of spectroscopic electromagnetic radiation sequentially interacts to select a desired wavelength. FIG. 4 herein, (which is FIG. 9 in a Patent to Liphardt et al. U.S. Pat. No. 7,345,762), is included herein for easy reference, as it shows one example that shows such an arrangement. FIG. 5 herein, (which is FIG. 2 in said U.S. Pat. No. 7,345,762), is also included herein to demonstrate a dual grating spectrometer that enhances resolution of produced wavelengths, and finds application in ellipsometer or polarimeter systems.
Another known Patent is U.S. Pat. No. 6,104,488 to LeVan. This Patent is focused on providing high single grating efficiency, with different orders of wavelengths being produced thereby detected by a single detector.
An article titled “A New Spectrometer Using Multiple Gratings With A Two-Dimensional Charge-Coupled Diode Array Detector”, Review of Scientific Instruments, Vol. 74, No. 6, June 2003, describes a special grating that consists of three laterally stacked sub-gratings to generate three wavelength ranges.
It is noted that the identified prior art is primarily focused on production of wavelength ranges.
Even in view of the known prior art there remains need for additional systems directed to optimizing application of a plurality of detectors and/or wavelength dispersing elements which are arranged sequentially, and wherein each follow-on wavelength dispersing element receives a reflected altered spectral content reflected beam of electromagnetic radiation from a preceding wavelength dispersing element, and wherein each wavelength dispersing element produces at least one + or − spectrum of dispersed wavelengths which are directed toward a related detector.